Chronic diabetic wounds are responsible for more than 27% of diabetic health care costs in the US annually, with total diabetic health costs annually exceeding $10.9 billion. Common treatment procedures are often inadequate and lead to complications and chronic non-healing ulcers. Insufficient vascularization is a major factor contributing to impaired wound healing of diabetic ulcers. The goal of our research is to develop a novel approach to treat chronic diabetic ulcers by applying a recent advancement in nano-biotechnology - a self- assembling peptide nanoscaffold - to modify the microenvironment of the ulcer. Our data for wound healing in genetically diabetic mice suggest that the peptide nanoscaffold provides a stable, protease-resistant environment which enables endothelial cell infiltration, promotes neovascularization and improves healing at 1 week after surgery. The objective of this R21 application is to determine the effects of the peptide treatment on early neovascularization (Aim 1) and on various components of the scaffold-mediated wound healing at the later healing stages (Aim 2), using excisional skin wound healing in murine models of type I and type II diabetes. We hypothesize that the RAD16-II peptide nanoscaffold will improve wound healing in mouse models of type I and type II diabetes by providing a granulation tissue substitute that promotes early angiogenesis and vasculogenesis and facilitates extracellular matrix deposition. Aim 1 will determine whether wound treatment with the peptide nanoscaffold promotes neovascularization through angiogenic, vasculogenic, or both mechanisms, using immunostaining for endothelial cell and endothelial precursor cell markers and cell proliferation, and Tie2/GFP bone marrow transplantation to identify precursor cells recruited from bone marrow. Aim 2 will demonstrate that wound treatment with the peptide nanoscaffold augments delayed wound healing at the final stages of healing process, and will determine which components of healing process (neovascularization, inflammation, cell proliferation, matrix remodeling) are influenced by this treatment. This will be achieved by assessment of wound morphology, neovascularization, inflammation, time of closure of epithelial gap, collagen deposition and wound breaking strength. This study will improve our understanding of the mechanisms for enhanced neovascularization in peptide nanoscaffold-treated wounds in the murine models of type I and type II diabetes. These results will enable purposeful modifications of the nanoscaffold, for example, via attaching signaling sequences to "fine tune" the microenvironment of the diabetic wounds and to facilitate the healing process, taking full advantage of the nanoscaffold technology. Significance of our approach is in application of a novel synthetic material with low immunogenicity to enhance neovascularization and modify extracellular environment of the diabetic wound. The impact of the proposed work is not limited to diabetic wound healing research;the results of this study will contribute to knowledge and will advance technology that will be of interest to a broad scientific community of researchers in vascular tissue engineering. Chronic diabetic wounds are responsible for more than 27% of diabetic health care costs in the US annually, with total health costs annually exceeding $10.9 billion. Common treatment procedures are often inadequate and lead to complications and chronic non- healing ulcers. PUBLIC HEALTH RELEVANCE:This study is focused on application of novel materials peptide nanoscaffolds- to restore angiogenic environment in the wound bed and enhance diabetic wound healing.